Abstract: The rotating biological contactor is a high efficient immobilized device for microorganism which is suitable for treating the acid mine drainage.The process conditions of the start-up and stabilizing stage of rotating biological contactor are studied.The test result shows that the start-up of reactor can be affected by six consecutive cultivations with 10% inoculation amount.With the repeated biofilm forming process, the cycle of Fe²⁺ oxidation is shortened continuously, from the initial 100 h to 70 h, and meanwhile, the biofilm's capacity of Fe²⁺ oxidation tends to become stable.The impact of the hydraulic retention time, rotating speed and inlet concentration on Fe2+ oxidation rate in a stable treatment process for acid mine drainage was investigated.The results show that are the best, the 4 h hydraulic retention time and the 7 r/min rational rotating speed.

Key words: Immobilized Acidithiobacillus ferrooxidans, Rotating biological contactor, Acid mine drainage